Plasmochemical Modification of Crofer 22APU for Intermediate-Temperature Solid Oxide Fuel Cell Interconnects Using RF...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Engineering

Background:

• Crofer 22APU ferritic stainless steel is a candidate for intermediate-temperature solid oxide fuel cell (IT-SOFC) interconnects.
• Surface modification is crucial to enhance the long-term performance and durability of SOFC components.

Purpose of the Study:

• To investigate the effects of plasmochemical modification, specifically a SiC_xN_y:H layer deposition, on Crofer 22APU steel.
• To evaluate the impact of N⁺ ion surface pre-modification on the steel's properties for IT-SOFC applications.

Main Methods:

• Radio-Frequency Plasma-Activated Chemical Vapor Deposition (RF PA CVD) was used to deposit SiC_xN_y:H layers.
• Surface analysis included IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS).
• Mechanical and electrical properties were assessed via microhardness, Young's modulus, wear rate, and electrical resistance measurements.

Main Results:

• Plasmochemical modification positively influenced surface hardness and Young's modulus.
• N⁺ ion pre-modification significantly improved high-temperature corrosion resistance compared to CVD-modified steel alone.
• The area-specific resistance was 0.01 Ω·cm², outperforming bare steel after 500 h at 1073 K.

Conclusions:

• The SiC_xN_y:H layer deposition, especially when preceded by N⁺ ion modification, yields superior properties for Crofer 22APU steel.
• This optimized surface modification enhances the potential of Crofer 22APU steel for IT-SOFC interconnect applications.